Actually, i dont believe they are separate, in game they are not independent of the ship, they do not move. They are hard points created on the ship mesh.
Though i believe weapon points can be added with research.
But in the "Vanilla" game i dont believe they add the additional points on the fly, as there is no mechanism in place to switch meshes mid game.
The Entrenchment expansion for the game does add this ability, for Starbases, Hangars and some structures, and im not quite sure, but they may add it for one of the capitals that adds weapon turrets, The TEC Marza i believe. But again, they are hard, non-moving additions.
There are those in the SOASE Community that believe such ability may be coming in a new expansion, but nothing official has been announced that i am aware of.
Hope this helps,
-Teal